Monitoring of harmful algal blooms along the Norwegian coast using bio-optical methods

A Norwegian monitoring system for harmful algal blooms, consisting of an Observer Network, the State Food Hygiene Control Agency, the Oceanographic Company of Norway, the Institute of Marine Research and the Directorate for Fisheries, is reviewed. Potentially harmful algae on the Norwegian coast are found primarily in four classes of phytoplankton, dinoflagellates, prymnesiophytes, diatoms and raphidophytes. The system consists of buoys designed for real-time, in situ monitoring and forecasting, and is used principally to provide an early warning to the aquaculture industry. The system allows detection of potentially toxic species, through a combination of physical, chemical, biological and bio-optical data. New datasets using bio-optical techniques on glass-fibre filters are also described, providing information on the composition and health of phytoplankton populations

Scientific Network of Experts: Interviewer Effects and Interviewer Training

Although the collection of survey data is undergoing a notable shift toward online and mixed-mode data collection methods (Baker et al., 2010; Groves, 2011), interviewers are still heavily involved in the majority of survey data collections that serve as a basis for important economic, educational, and public policy decisions. Research supports the notion that interviewer characteristics and task-specific skill levels significantly influence the resulting data quality (see, e.g. Ackermann-Piek, 2018; Billiet & Loosveldt, 1988; Dahlhamer, Cynamon, Gentleman, Piani, & Weiler, 2010; Durand, 2005; Fowler Jr., 1991; Hox & de Leeuw, 2002; Jäckle, Lynn, Sinibaldi, & Tipping, 2013; Sakshaug, Tutz, & Kreuter, 2013; Schnell & Trappman, 2006; Vannette & Krosnick, 2018; West & Blom, 2017; West, Kreuter, & Jaenichen, 2013). Thus, it is not surprising, that the international survey research community has sought opportunities to facilitate intensive exchanges between survey researchers on topics related to interviewer training procedures, fieldwork processes, and interviewer effects at international workshops and conferences (e.g. Workshop on Explaining interviewer effects in interviewer-mediated surveys, Germany: Mannheim, April 2013; Interviewer workshop, USA Nebraska: Lincoln, February 2019; Conferences of the European Survey Research Association, every other year at changing locations). However, such occurrences tend to be sporadic, one-off events, not designed to promote a continuous, ongoing dialogue of interviewer-related issues in the field. Furthermore, while most of the interviewer literature reports findings on interviewer effects and interviewer training, there is a lack of overarching recommendations and standards for reduction of interviewer effects and the implementation of appropriate interviewer training methods in interviewer-administered surveys. For example, international recommendations for interviewer training are typically quite broad and do not include a high level of detail suitable for prescriptive and standardized implementation in the field (Alcser, Clemens, Holland, Guyer, & Hu, 2016; Daikeler, Silber, Bosnjak, Zabal, & Martin, 2017; Fowler Jr. & Mangione, 1990; Lessler, Eyerman, & Wang, 2008). In the following proposal, we describe our vision to set up a multi-year scientific exchange and cooperation among a core group of international methods experts on topics related to interviewer involvement in the implementation of scientific surveys. We aim to start with three-year pilot phase to build up an infrastructure for regular knowledge exchanges and sharing of materials. Within this pilot phase, annual or biannual meetings will be organized to discuss best practices, exchange ideas, and identify research gaps on pressing topics pertinent to interviewer surveys. As the major outcome of this scientific network, we plan the production of research-based standards and recommendations reports to be published on various interviewer-related topics

Linking PIAAC Data to Individual Administrative Data: Insights from a German Pilot Project

Linking survey data to administrative data offers researchers many opportunities. In particular, it enables them to enrich survey data with additional information without increasing the burden on respondents. German PIAAC data on individual skills, for example, can be combined with administrative data on individual employment histories. However, as the linkage of survey data with administrative data records requires the consent of respondents, there may be bias in the linked dataset if only a subsample of respondents - for example, high-educated individuals - give their consent. The present chapter provides an overview of the pilot project about linking the German PIAAC data with individual administrative data. In a first step, we illustrate characteristics of the linkable datasets and describe the linkage process and its methodological challenges. In a second step, we provide an illustrative example of the use of the linked data and investigate how the skills assessed in PIAAC are associated with the linkage decision

The Impact of Nurse Continuity on Biosocial Survey Participation

Biological measurements (or biomeasures) are increasingly being collected in large longitudinal biosocial surveys, enabling researchers to exploit the advantages of social science data with objective health measures to better understand how health and social behaviour interact over time. However, not all survey respondents are willing to take part in the biomeasure component of biosocial surveys, even when the measures are administered by certified medical professionals, such as nurses. Thus, understanding factors which affect participation in biomeasure collection is essential for making valid biosocial inferences about the population. Previous research has shown that interviewer continuity can be useful for optimizing longitudinal survey participation, but it is yet unknown if nurse continuity impacts the likelihood of participation in biomeasure collection. We investigated the impact of nurse continuity on nonresponse to biomeasure collection in waves 4 and 6 of the English Longitudinal Study of Ageing (ELSA). Using cross-classified multilevel models, we find that switching nurses between waves does not negatively impact participation in biomeasure collection, and sometimes can be beneficial, particularly for previous wave nonrespondents. The practical implication is that biosocial surveys may not need to employ strict nurse continuity protocols to maximize participation in subsequent waves of biomeasure data collection

The Need to Account for Complex Sampling Features when Analyzing Establishment Survey Data: An Illustration using the 2013 Business Research and Development and Innovation Survey (BRDIS)

The importance of correctly accounting for complex sampling features when generating finite population inferences based on complex sample survey data sets has now been clearly established in a variety of fields, including those in both statistical and non-statistical domains. Unfortunately, recent studies of analytic error have suggested that many secondary analysts of survey data do not ultimately account for these sampling features when analyzing their data, for a variety of possible reasons (e.g., poor documentation, or a data producer may not provide the information in a public-use data set). The research in this area has focused exclusively on analyses of household survey data, and individual respondents. No research to date has considered how analysts are approaching the data collected in establishment surveys, and whether published articles advancing science based on analyses of establishment behaviors and outcomes are correctly accounting for complex sampling features. This article presents alternative analyses of real data from the 2013 Business Research and Development and Innovation Survey (BRDIS), and shows that a failure to account for the complex design features of the sample underlying these data can lead to substantial differences in inferences about the target population of establishments for the BRDIS

Yielding behaviour and interaction at bicycle crossings

The main purpose of this study was to learn more about how bicyclists and motor vehicle drivers in some Swedish cities interact at intersections and how the yielding rules, different intersection designs, vehicle flows and speed affect the behaviour. Field studies were performed at 25 crossings for six hours each. Cycle crossings on links, at three- and four-armed intersections as well as at roundabouts were studied. Preliminary results show that yielding rules are not enough to make road users behave as intended; even when there are yielding signs and markings before the bicycle crossing, 30% of the motor vehicle drivers do not yield to bicyclists. Fewer yield to bicyclists when motor vehicle speed is higher, when motor vehicle flow is larger and when bicycle flow is smaller. Speeds below 30 km/h seem to produce quite favourable conditions for an interaction with a high degree of equity, efficiency and safety for both road users no matter whether car drivers have to yield according to the rules or not. Motor vehicle drivers are most likely to give way to bicyclists when the bicycle crossing is next to a roundabout and least likely to give way when it is situated on a link. The conclusion is that there is a certain amount of drivers that do not obey the yielding rules and presumably rely on their larger mass and better protection. It is therefore very important that the road design allows for active interaction between the road user groups to get a more equal situation between motor vehicle drivers and bicyclists as well as safe and secure bicycle crossings. Speed is obviously the key issue

The reliability of adult self-reported height : The role of interviewers

Surveys serve as an important source of information on key anthropometric characteristics such as body height or weight in the population. Such data are often obtained by directly asking respondents to report those values. Numerous studies have examined measurement errors in this context by comparing reported to measured values. However, little is known on the role of interviewers on the prevalence of irregularities in anthropometric survey data. In this study, we explore such interviewer effects in two ways. First, we use data from the US National Health and Nutrition Examination Survey and the UK Household Longitudinal Study to evaluate whether differences between reported and measured values are clustered within interviewers. Second, we investigate changes in adult self-reported height over survey waves in two German large-scale panel surveys. Here, we exploit that height should be constant over time for the majority of adult age groups. In both analyses, we use multilevel location-scale models to identify interviewers who enhance reporting errors and interviewers for whom unlikely height changes over waves occur frequently. Our results reveal that interviewers can play a prominent role in differences between reported and measured height values and changes in reported height over survey waves. We further provide an analysis of the consequences of height misreporting on substantive regression coefficients where we especially focus on the role of interviewers who reinforce reporting errors and unlikely height changes

Parametric bootstrap mean squared error of a small area multivariate EBLUP

© 2018, © 2018 Taylor & Francis Group, LLC. This article deals with mean squared error (MSE) estimation of a multivariate empirical best linear unbiased predictor (MEBLUP) under the unit-level multivariate nested-errors regression model for small area estimation via parametric bootstrap. A simulation study is designed to evaluate the performance of our algorithm and compare it with the univariate case bootstrap MSE which has been shown to be consistent to the true MSE. The simulation shows that, in line with the literature, MEBLUP provides unbiased estimates with lower MSE than EBLUP. We also provide a short empirical analysis based on real data collected from the U.S. Department of Agriculture

Separation between pedestrians and bicyclists

In the effort to separate pedestrian and bicycle traffic from motorised traffic the solution often is to let the pedestrians and bicyclists share space. However, combined pedestrian and bicycle paths lead to problems for both pedestrians and bicyclists; for pedestrians it is a security and safety problem and for bicyclists a mobility problem. Seniors and visually impaired pedestrians are especially concerned as they often feel insecure when cyclists pass close to them, especially as they neither can see nor hear cyclists coming from behind. The safety problem is primarily linked to pedestrians walking on the bicycle side of the tracks. Designing the tracks so that the pedestrians and bicyclists keep to their side respectively is important to improve the situation. Field studies were performed at over 100 pedestrian and bicycle tracks and the results were analysed with respect to materials, separation line, flow, signs, dimensions, road markings and surroundings. The results show that the design has a great impact on whether the road users keep to their side of the pedestrian and bicycle tracks or not. The most efficient design seems to be a difference in material, asphalt on the bicycle side and tiles on the pedestrian side, together with a separation of the two sides, e.g. by paving stones or curbs. Signing has no impact at all whereas the road markings has a great impact, which is interesting both from a perceptional view point and also from the point of view that Swedish rules do not support the use of markings but signing

Obtaining Record Linkage Consent: Results from a Wording Experiment in Germany

Many sample surveys ask respondents for consent to link their survey information with administrative sources. There is significant variation in how linkage requests are administered and little experimental evidence to suggest which approaches are useful for achieving high consent rates. A common approach is to emphasize the positive benefits of linkage to respondents. However, some evidence suggests that emphasizing the negative consequences of not consenting to linkage is a more effective strategy. To further examine this issue, we conducted a gain-loss framing experiment in which we emphasized the benefit (gain) of linking or the negative consequence (loss) of not linking one’s data as it related to the usefulness of their survey responses. In addition, we explored a sunk-prospective costs rationale by varying the emphasis on response usefulness for responses that the respondent had already provided prior to the linkage request (sunk costs) and responses that would be provided after the linkage request (prospective costs). We found a significant interaction between gain-loss framing and the sunk-prospective costs rationale: respondents in the gain-framing condition consented to linkage at a higher rate than those in the loss-framing condition when response usefulness was emphasized for responses to subsequent survey items. Conversely, the opposite pattern was observed when response usefulness was emphasized for responses that had already been provided: loss-framing resulted in a higher consent rate than the gain-framing, but this result did not reach statistical significance